U.S. Transportation Secretary Ray LaHood warned California lawmakers Thursday not to wait until fall for a vote on high-speed rail, urging its approval in a budget vote next month.

"We need to make sure that the commitment is there to obligate the money," LaHood told reporters at the Capitol, where he was meeting with lawmakers and Gov. Jerry Brown.

The state's commitment, LaHood said, will be demonstrated when lawmakers "put it in the budget and take a vote on it."

Brown and the California High-Speed Rail Authority want to start construction on a $68 billion rail project by early next year, proposing initially to use $2.6 billion in state rail bond funds and $3.3 billion in federal funds.

Lawmakers remain skeptical, however, and the nonpartisan Legislative Analyst's Office has recommended against it.

LaHood said he was at the Capitol to reiterate the Obama administration's commitment to high-speed rail, while "checking signals" in the Legislature. He said the suggestion by some lawmakers that they may need more time to consider the proposal – perhaps pushing an an up or down vote into the fall – is unacceptable.

"We want to make sure that our partners here understand what's at stake," he said. "We can't wait until the end of summer."

LaHood declined to say what the administration will do if the Legislature does delay, saying, "I'm going to operate on the assumption that people are going to act in good faith."

LaHood praised the Brown administration for a project redesign this year that dramatically reduced its price, from $98 billion.

"My message to the Assembly, to the leadership, is that we need to make sure that there's a continued, strong commitment on the part of the Assembly, as reflected in their budget," he said.

LaHood's comments drew an immediate rebuke from Sen. Doug LaMalfa, R-Richvale, a longtime critic of the rail project. "Secretary LaHood's demand boils down to a belief that Washington, D.C. knows best, a point of view I couldn't disagree with more strongly," he said in a statement.

The Legislative Analyst's Office has criticized the project for its reliance in future years on uncertain federal funding. State Sen. Joe Simitian, the Palo Alto Democrat who chairs the budget subcommittee considering high-speed rail, has said the administration's recent changes to the project would likely require more time to consider beyond when the state budget is adopted next month.